Field of the Disclosure
The present disclosure relates to an operating device that is connected to a controller for controlling an operation target and inputting an operation signal for operating the operation target to the controller.
Background of the Disclosure
As a conventional example, an operating device may be connected to a numerical controller of an NC machine tool. An NC machine tool typically includes a machining mechanism performing operations for machining a workpiece and a numerical controller controlling the operations of the machining mechanism. For example, in a case of a lathe, the machining mechanism includes a spindle holding and rotating a workpiece, a drive mechanism for the spindle, a tool rest holding a tool, a feed mechanism moving the tool rest in predetermined axis directions, and so on, whereas in a case of a machining center, the machining mechanism includes a table holding the workpiece, a spindle holding a tool, a drive mechanism for the spindle, a feed mechanism relatively moving the table and the spindle in predetermined axis directions, and so on.
Further, a typical operating device includes a display for displaying the status of the machining mechanism and various types of machining information and an operation unit having operation keys for inputting operation signals to the numerical controller; furthermore, in recent years, there is an operating device configured so that a touch panel having the so-called man-machine interface function forms the display and the operation unit, operation keys as softkeys are displayed on the touch panel, and when an operator presses the operation keys, corresponding operation signals are input to the numerical controller.
As for such a touch panel, various touch panels have conventionally been proposed, such as a touch key and a touch screen. As for the touch key, a capacitance type touch key is commonly used, which has a touch electrode formed by materials such as a printed circuit board, an ITO (indium tin oxide) film, and conductive rubber and which is configured to determine whether the key is ON or OFF by measuring capacitance generated between the key and a human body.
Further, as for the touch screen, there is similarly a capacitance type; besides, there are a resistance film type, an optical, and a sonic type. Of these types of touch screens, the capacitance type touch screen includes a self-capacitance detection type and a mutual-capacitance detection type; both of them have electrodes formed by materials such as a printed circuit board, an ITO film, and so on and arranged in a matrix form in X and Y directions.
As shown in FIG. 8, a mutual-capacitance detection type touch screen has electrodes formed in a grid-like form by arranging band-shaped wires 101 in the X and Y directions so that the wires 101 in X direction are orthogonal to the wires 101 in the Y direction. As shown in FIG. 9, this mutual-capacitance detection type touch screen has a configuration in which its electrodes are composed of receivers 102 and transmitters 103 and the receivers 102 are grounded to a ground; an electric field (field coupling) 104 occurs between the receivers 102 and the transmitters 103 as shown in FIG. 9 when a pulse is input to the transmitters 103. Further, as shown in FIG. 10, when an operator's finger 105 approaches the transmitter 103, the electric field 104 between the receiver 102 and the transmitter 103 is reduced because a part 104a of the electric field occurs between the transmitter 103 and the operator's finger 105; therefore, touch of the operator's finger 105 is detected by measuring reduction in charge accompanying the reduction of the electric field 104.
On the other hand, as shown in FIG. 11, a self-capacitance detection type touch screen has a configuration in which rhombic electrodes 110 are connected together in the X and Y directions and they are arranged in a lattice pattern. As shown in FIG. 12, in this self-capacitance detection type touch screen, parasitic capacitance is generated between each of the electrode 110 and a ground pattern of a printed circuit board or a metal frame positioned around the electrode 110. Further, as shown in FIG. 13, when an operator' s finger 105 approaches the electrode 110, capacitance is generated between the operator's finger 105 and the electrode 110 because the operator is grounded to a virtual ground, which results in increase in capacitance in the electrode 110. In the self-capacitance detection type touch screen, touch of the operator's finger 105 is detected by measuring the increase in the capacitance in the electrode 110.
It is noted that, as an example of inventions that relate to a mutual-capacitance detection type touch screen, the invention disclosed in Japanese Unexamined Patent Application Publication No. 2012-502397 has conventionally been known.